Adding fan behind refrigerator...worthwhile??

StirCrazy wrote:

SJ-Chris wrote:
Added a 3rd fan and repositioned a few things. Cleaned up the wiring. I'll be taking it out in a week and we'll see how it does. This next trip will only be in ~80 degree weather, so I don't know if the fans will come on often and/or be of much help. The real test will be the next time I am boondocking in 95F+ temps.



These 3 fans will move 15cfm x 3 = 45cfm in theory. Running a test right now in ~94F temps while in storage.

-Chris

Depending on the baffle setup those fans may not make a difference. The normal way to install them is at the top vent sucking out and to insure you have the baffle setup properly around the fins on the heat exchanger to the air is directed through the fins. the reason the top sucking out is more effective is a bunch of laminar airflow and thermal dynamics stuff that would take me fore ever to type but essentially if you baffle the top exchanger section properly and just have one fan drawing out (maybe two depending on the space size) this will direct the air flow over the fins and ensure proper heat exchange. Just using a bunch of fans at the bottom and forcing more air in will force more air through but you're not controlling where you want it or getting a smooth high velocity air flow. you're getting chaotic and slow flow which won't cool as effectively.

Thanks for the feedback.

If I had the choice (translation: If it were easy enough to do), I would rather have a fan or two at the top roof vent sucking air from the behind the fridge area below and blowing it out the roof vent more directly, as I believe that would be more effective at forcing hot air out of the refrigerator area. But installing down below on the side panel was a lot easier.

The way that my side vent fans are set up is that they are sucking air from right next to the side vent slot openings. I believe this will pull cooler air in from outside, blowing it up behind the backside of the refrigerator. There is nowhere (practically speaking) for the air to flow but up out the roof vent. In doing so, it will pull heat from everywhere behind the refrigerator. This will aide in better cooling.

I ran a somewhat controlled test with just 2 of the fans installed. Ran the fridge for 24hrs on back to back 90F days. One day without the fans on. One day with the fans on. When the fans were on, at 3pm at the peak heat of the day, the freezer and fridge were both 6F cooler on the day the fans were running. So it seems like they are helping. I added a 3rd fan just because and I'm hoping that helps even more. We'll see.

Happy Camping!
Chris